A polishing composition containing abrasive grains is used for polishing, for example, a silicon substrate (see Patent document 1). In order to stabilize the quality of a polished product obtained by polishing an object, it is important to reduce aggregates in a polishing composition. In this regard, Patent document 2 discloses a technique for enhancing the dispersibility of abrasive grains. Patent document 3 discloses a technique in which a specific polymer compound is added to a concentrated liquid of a polishing composition to improve the storage stability of the concentrated liquid.